High-Speed Rotational Atherectomy during Transradial<br />
Percutaneous Coronary Intervention

The transradial approach to percutaneous coronary intervention (PCI) is established as a safe procedure with improved patient comfort and early ambulation.^1–3 This has translated into early discharge with reduced procedural costs leading to outpatient PCI.^4,5
Increasing numbers of patients are presenting with lesion morphology that requires a debulking strategy. Traditionally, high-speed rotational atherectomy (HSRA) has been performed via the femoral approach using 7 and 8 Fr catheters, and occasionally 9 Fr, to allow the use of a large-sized burr, which limited its use during 6 Fr radial PCI. However, using a smaller burr size would be more than adequate for partial debulking to allow the alteration of plaque compliance and facilitate stenting. Furthermore, operators for whom the radial artery is the default approach have usually scheduled patients for elective HSRA via the femoral route.
The aim of this retrospective review was to evaluate the success and outcome of HSRA during radial artery PCI. Such an approach represents an alternative to the femoral method and can lead to reduced access site complications with improved patient comfort. It would also avoid access limitations in patients with peripheral vascular disease.

Methods
The patient population comprised all consecutive patients undergoing HSRA during radial PCI between January 2005 and April 2007. Twenty-nine consecutive radial procedures in 28 patients were performed in this period out of a total of 68 procedures. All patients who underwent HSRA were identified from our Minerva Electronic database and the notes were retrieved and reviewed in a retrospective fashion, with the information collected in a predesigned form. Data were then entered into a computer and analyzed. Five random sets of notes were cross-reviewed by a second operator to ensure correct data collection. Continuous data are shown as mean values with standard deviation or range. Categorical data are shown as percentages with absolute numbers. All analyses were performed using SAS software for Windows, Version 8.2 (SAS Inc., Chicago, Illinois).
The technique employed for transradial procedures has been described previously³ with the use of a 6 Fr sheath system (Cook Cardiology, Letchworth, Hertfordshire, United Kingdom). MUTA or Q-guiding catheters were used for the left coronary artery, and an Amplatz or right Judkins catheter for the right coronary artery (RCA), depending on the operator’s preference. In twenty-two cases (75.8%), 6 Fr guide catheters were used, and 7 Fr in the remainder. In 1 case, the catheterwas upgraded from 6 to 7 Fr at the beginning of the procedure in anticipation of the need to use a 1.75 mm burr.
Heparin was used in all cases at a dose of 70–100 units/kg, with abciximab initiated in 7 patients as a bolus and 12-hour postprocedure infusion. All patients were loaded with 600 mg of aspirin and 600 mg of clopidogrel more than 6 hours prior to the procedure. Aspirin was continued indefinitely, and clopidogrel for 4 weeks in bare-metal stent patients, and for at least 1 year in drug-eluting stent patients.
The range of burr size used was 1.25–1.75 mm. Twenty- seven lesions were treated with one size, and 2 with two different-sized burrs. In 4 lesions, the largest burr was 1.25 mm, in 23 lesions it was 1.5 mm, and in 2 it was 1.75 mm. All patients underwent adjunctive stent implantation in all lesions. At the end of the procedure, the radial sheath was removed and hemostasis achieved using a unilateral pressure system (TR Band, Terumo Medical Corp., New Jersey).

Results

The patients’ clinical and demographic characteristics are summarized in Table 1. Twenty-eight patients and procedures were performed with a total of 29 lesions treated. All procedures were successfully carried out transradially. Of the 28 patients, 4 were urgent and 12 were unplanned HSRA.
All were de novo lesions. The distribution of the lesions was as follows: 15 (51.8%) were located in the left anterior descending artery (LAD), 11 (37.9%) in the RCA, and 3 (10.3%) in the left circumflex artery (LCx). Twenty-one of the lesions (72.4%) were proximal, 1 (3.4%) ostial, 5 (17.2%) mid, and 2 (6.8%) distal. The majority of the lesions were type C classification, 21 (72.4%) and 5 (17.3%) were type B2 .
The mean vessel diameter was 2.7 ± 0.5 mm (2.25–4.0 mm), and the mean length of stents deployed was 23.5 ± 6.7 mm (18–63 mm). A total of 44 stents were implanted, 28 (63.6%) of which were drug-eluting stents and 16 (36.3%) were bare-metal stents. The procedure time was 94 ± 35 minutes (range 50–180). From June 2006 (the start of the outpatient PCI program), 7 out of 8 patients were discharged home the same day, with 1 admitted following the occurrence of pericardial effusion. The procedure was reported as successful in all lesions except one that was reported as a partial success due to an underexpanded stent. This patient later developed instent restenosis and was referred for coronary artery bypass grafting (CABG). Postprocedural creatine kinase-MB was available in 26 patients, and none had a CK-MB rise greater than 2 times the upper limit of normal. The average CK-MB rise was 4.7 ± 2.^2–9
All procedures were completed from the radial artery, with no major vascular complications, and the radial artery pulse was preserved in all patients postprocedure. One patient had evidence of minor brachial artery dissection when the guide catheter was upsized to 7 Fr, and the procedure was completed with no sequelae and with normal flow on angiography at the end. Another patient developed pericardial effusion after the procedure and was treated successfully with pericardial drain with no adverse consequences. Similarly, 1 patient had a respiratory arrest that was thought to be an allergic reaction; he was intubated for a short period and recovered with no long-term effects. There were no major adverse cardiac events related to the procedure.
One patient was readmitted 1 week later with an acute coronary syndrome, and repeat coronary angiography showed evidence of stent thrombosis that was treated successfully with balloon angioplasty. The patient admitted to not taking his clopidogrel or aspirin after the procedure. Another patient had recurrent symptoms with evidence of in-stent restenosis in his LAD and underwent successful CABG. This patient was advised to undergo CABG, but had declined it prior to PCI and HSRA. Another patient had an occluded stent in his RCA 4 months following HSRA with unsuccessful repeat PCI and was managed medically. Similarly, another patient developed mild angina and was also managed medically.

Discussion
This study shows that HSRA can be safely and successfully performed via the radial artery. In a high proportion of patients, HSRA was not the initial strategy, but was performed successfully via a 6 Fr radial guiding catheter without difficulty. This study also demonstrates that the use of the radial approach would not preclude HSRA in patients in need of a debulking procedure. There were 12 ad hoc cases where the lesion could not be crossed with a balloon and the procedure upgraded to HSRA, and would have had to be rescheduled for a femoral approach procedure had it not been feasible via the radial artery using a 6 Fr catheter. The radial approach is advantageous in treating patients with peripheral vascular disease and poor femoral access and in people at high risk of bleeding such as the elderly and obese patients.
This study highlights the feasibility and safety of HSRA via the transradial approach. Although some operators perform this procedure via the radial approach, the majority remain hesitant and continue to perform HSRA via the femoral approach.
Most patients were mobile immediately after the procedure and sheath removal. Our patients were kept in the hospital overnight following the procedure, however, 7 patients were treated on an outpatient basis and discharged home on the same day once our center’s outpatient radial PCI program began. This indicates that HSRA does not affect this approach and patients can be treated on an outpatient basis.
The use of small burr sizes (1.25 mm and 1.5 mm) did not produce complete debulking, however, it allowed for the use of a 6 Fr guiding catheter in the radial artery and was successful in all patients. Small burrs are effective for partial debulking and lead to alteration of plaque compliance, which facilitates further ballooning and stenting.4 In 1 patient, however, there was evidence of underdeployment of the stent that resulted in in-stent restenosis requiring further intervention. Similarly, early on in our radial procedures, a 7 Fr guiding catheter was utilized on 6 occasions, however, with increasing experience, all subsequent procedure were completed with a 6 Fr guide catheter.
The complication rate in transradial cases is reported to occur in 2–10% of cases.⁶ Despite the relatively prolonged procedure time in our series (94 minutes), all radial pulses were present after the procedure in all patients. Cannulation time, heparin regimen and the size of the artery are thought to influence the rate of radial artery occlusion.^7,8 The use of a 6 Fr sheath may have helped to reduce the risk of radial artery occlusion. In a previous small series, > 50% of patients had a radial artery diameter > 2.8 mm, which would accept an 8 Fr sheath. Similarly, none of our patients had any major vascular complications or complained of excessive pain, discomfort or spasm during cannulation or catheter manipulation, except 1 patient who had a minor dissection that did not result in any adverse events. This may indicate that frequent instrumentation through the radial artery may result in complications such as dissection, however, there were no such concerns in our patient.
The majority of the procedures were carried out successfully with a 6 Fr guide and a 1.5 mm burr. We believe that smaller burr size would be more than adequate for plaque compliance alteration and for partial debulking, which would help facilitate ballooning and stenting. This is born out in the successful outcomes in all of our patients with arteries up to 4 mm in diameter and most lesions of type C classification. One patient, however, had a partially successful procedure due to an underdeployed stent, which may indicate that the debulking was not sufficient to produce an optimal result. Furthermore, it is evident that the use of a 7 Fr guiding catheter is feasible through the radial artery in the event that the operator believes there is a need for larger-sized burrs. These larger catheters can be introduced from the start, or alternatively, be upsized during the procedure.
No difficulties were encountered with the 6 Fr catheters, which offered enough support to complete the procedures. However, 7 Fr catheters give more support, although the availability of a dedicated radial catheter curve in this size remains limited.
The strategy of lesion modification with a small burr size prior to subsequent adjunctive treatment with high-pressure ballooning and stenting support a conservative approach in debulking, rather than an aggressive one with larger burr sizes,^9,10 which would allow the use of the radial artery and 6 Fr guiding catheters. Larger studies are required to assess this approach, as this series involves a small number of patients, a retrospective analysis and inadequate power to assess safety.

Conclusion
This study demonstrates the safety and feasibility of HSRA during radial coronary intervention using a 6 Fr guiding catheter. It extends the clinical experience with the radial approach to HSRA with demonstrable excellent results and the added benefit of increased patient comfort, reduced access site complications and the advantage of early ambulation and discharge. Larger studies would further help establish this approach and assess its safety.

References

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